You can set OS X to only open applications downloaded from the Apple Store, or from the Apple Store and/or developers with a valid Developer's ID, or from anywhere at all.
So, yeah... Kinda makes the knee-jerk snarky "control-freak", "locked-down", "walled garden" comments seem rather puerile when anyone can permanently disable Gatekeeper at any time. (OS X DOES, however -- quelle horreur! -- require that you input your password before changing that security setting. I guess that must be that heavy-handed control-freakery at work...)